1. Field of the Invention
The present invention relates to a wrapping sheet used to wrap and maintain a fully folded air bag, but that, as the air bag is being inflated, tears under the pressure exerted by the expanding air bag.
2. Related Art
Conventionally, a wrapping sheet includes an engagement piece that is fitted on attachment shafts projecting from an air bag, and when the engagement piece for the wrapping sheet has been fitted on the attachment shafts, the air bag, for which folding has been completed, is retained, undisturbed, within the wrapping sheet. The attachment shafts projecting from the air bag can be either retainer bolts or defuser bolts, and are employed to secure the folded air bag in a storage portion. Furthermore, one presently available conventional wrapping sheet has not only as a function for preventing the disarrangement of a folded air bag, but also as a protective cover, which when the folded air bag is inflated from a storage case, prevents damage to the air bag by the storage case (see, for example, JP-A-2004-314763).
Another conventional wrapping sheet serves as means for adjusting the shape of an air bag when inflated, from the folded state, and propelled outward from the storage portion (see, for example, JP-A-2002-187512).
There is one other conventional wrapping sheet that is not used for maintaining the shape of a folded air bag, but wraps part of the folded air bag by coupling that part with a portion of the wrapping sheet, and provides a sealing function for preventing the leakage of an air bag inflation gas (see, for example, JP-A-2006-044612).
With the conventional wrapping sheets referenced above, although each of these wrapping sheets can satisfactorily wrap and prevent the disarrangement of a folded air bag, adjusting the position of such a wrapping sheet during a folding process is not possible. Therefore, to ensure that an air bag will have a predetermined shape when the folding process has been completed, an improved folding process is required.